The present invention relates to ligands, ligand-metal compositions, complexes, and catalysts useful in the polymerization of olefins and other transformations, as well as processes for the polymerization of monomers (including vinylidene aromatic monomers) and to the novel polymers obtained thereby.
Ancillary (or spectator) ligand-metal coordination complexes (including organometallic complexes) and compositions are useful as catalysts, additives, stoichiometric reagents, solid-state precursors, therapeutic reagents and drugs. In the field of polymerization catalysis, and particularly in connection with homogeneous catalysts including single site catalysis, the ancillary ligand typically offers opportunities to modify the electronic and/or steric environment surrounding an active metal center. This allows the ancillary ligand to assist in the creation of possibly different polymers, as well as to control many of the important polymerization characteristics of a process employing such complexes. For example, the ancillary ligands may have a large effect on the catalytic efficiency, the useful operating temperature and pressure of the catalytic process, the polymerization rate and polymer yield per unit time, and the ability to control the molecular weight of the product. Group 4 based single site and other homogeneous catalysts are generally known for catalyzing a variety of coordination polymerization reactions. See, generally, “The Search for New-Generation Olefin Polymerization Catalysts: Life beyond Metallocenes”, Gibson, et al., Angew. Chem. Int. Ed. 1999, 38, 428-447; Organometallics 1999, 18, 3649-3670 and “Advances in Non-Metallocene Olefin Polymerization Catalysts”, Gibson, et al., Chem. Rev. 2003, 103, 283-315.
The polymerization of vinylidene aromatic monomers, especially styrene and substituted styrenes, to form non-stereoregular polymers has proven difficult to accomplish using non-metallocene catalysts. Recently, Okuda and other researchers have reported the results of their investigations, See, Okuda et al., J. Organometallic Chem., 689 (2004) 4636-4641, Okuda et al., Organometallics, 224, 2971-2982 (2005), WO 2004/078765, Kim, et al., Macromol. Rapid Commun. 2004, 25, 1319-1323, and Proto et al., Macromolecules 2003, 36, 5942-5946. In general, the known processes have been limited to the use of relatively low reaction temperatures and the production of undifferentiated polymers.
Despite the efforts of many workers in the field, a need remains for commercially suitable catalyst systems for the polymerization of monomers, and in particular for the homopolymerization or copolymerization of vinylidene aromatic monomers, especially styrene or substituted styrenes, for the production of polymers having molecular weights high enough for general commercial use, and variable tacticities, at high reaction temperatures. In particular, what is needed is a catalyst or family of catalysts capable of making a range of vinylidene aromatic polymers with differing degrees of stereoregularity that can be controlled by the appropriate choice of catalyst and conditions. A range of product opportunities could then exist, including polymers uniquely suited for preparation via high temperature solution polymerization processes.
In particular, solution polymerization processes running at greater than 100° C. using coordination catalysts capable of producing vinylidene aromatic polymers with commercially useful molecular weights and molecular architecture are still desired in the art.